Click on image to enlarge: North is at 4 o' clock.Objects: Messier 81 (Bode's Galaxy, NGC 3031, left of frame) and Messier 82 (The Cigar Galaxy, NGC 3034, right)
Type: Galaxies
Distances: 4.5 million light years (M81), 17 million light years (M82)
Distances: 4.5 million light years (M81), 17 million light years (M82)
Constellation: Ursa Major
Date: 23 March 2009
Equipment: SXV-H9, Vixen 114mm aperture f5.3 ED refractor, UV/IR filter
Subframes: 30 x 120 seconds 2x2 binned, no flats or darks, stacked in AIP4Win, tweaked in AstroArt and PSP7.
After nearly a whole month of haze and cloud, at last an opportunity to get some imaging in! I had caught M81 previously and had decided that I would like to get an image of M81 and its attendant "starburst" companion, M82, in the same frame, as the SXV-H9 chip size with my refractor was just about big enough.
This proved a little more tricky to frame than it looked. I'd also got a bit rusty on technique after nearly a month off! It took me a lot longer than usual to get the two galaxies framed, and I was conscious that my last few imaging sessions had been cut short by the appearance of clouds. In the end, I settled for the above, although my SkyMap Pro tells me I could have done a lot better by rotating the camera another 40 degrees or so.
I normally don't bother with dark frames as the SXV-H9 is pretty low on noise given the short exposure I normally use. Flats are, however, essential. However, on this occasion, I inadvertently took the camera off of the telescope when I finished the session. I normally always leave it on, so that I can shoot flats against a white screen in my garage next day.
I'd forgotten that part of my routine because of the weather-enforced layoff. Moving the camera in relation to the telescope obviously invalidates any flat-fielding, so I resorted to gradient and noise filters to hammer out backgrounds that would normally be handled by flats.
The resultant image isn't as detailed as I'd like, but it's not bad. One of these days I'll get a session in where I get everything right...
M81 seems pretty popular on the SPA gallery at the moment, so I haven't posted my effort because there are better ones on there already. I particularly liked Olly Penrice's shot, although he does enjoy dark skies deep in Southern France so he tells us, which is cheating really...
I'm only jealous...
Equipment: SXV-H9, Vixen 114mm aperture f5.3 ED refractor, UV/IR filter
Subframes: 30 x 120 seconds 2x2 binned, no flats or darks, stacked in AIP4Win, tweaked in AstroArt and PSP7.
After nearly a whole month of haze and cloud, at last an opportunity to get some imaging in! I had caught M81 previously and had decided that I would like to get an image of M81 and its attendant "starburst" companion, M82, in the same frame, as the SXV-H9 chip size with my refractor was just about big enough.
This proved a little more tricky to frame than it looked. I'd also got a bit rusty on technique after nearly a month off! It took me a lot longer than usual to get the two galaxies framed, and I was conscious that my last few imaging sessions had been cut short by the appearance of clouds. In the end, I settled for the above, although my SkyMap Pro tells me I could have done a lot better by rotating the camera another 40 degrees or so.
I normally don't bother with dark frames as the SXV-H9 is pretty low on noise given the short exposure I normally use. Flats are, however, essential. However, on this occasion, I inadvertently took the camera off of the telescope when I finished the session. I normally always leave it on, so that I can shoot flats against a white screen in my garage next day.
I'd forgotten that part of my routine because of the weather-enforced layoff. Moving the camera in relation to the telescope obviously invalidates any flat-fielding, so I resorted to gradient and noise filters to hammer out backgrounds that would normally be handled by flats.
The resultant image isn't as detailed as I'd like, but it's not bad. One of these days I'll get a session in where I get everything right...
M81 seems pretty popular on the SPA gallery at the moment, so I haven't posted my effort because there are better ones on there already. I particularly liked Olly Penrice's shot, although he does enjoy dark skies deep in Southern France so he tells us, which is cheating really...
I'm only jealous...
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